In British English, the distinction is that we use 'the' when we are talking about a specific building, and don't use it when we are talking about an activity associated with a building.Originally Posted by paulb
For example:
If someone is ill and needs hospital treatment, we would say "he is going to hospital", without an article. If, on the other hand, you are talking about a doctor going to work, we would say "he is going to the hospital".
A child "goes to school", but a parent "goes to the school" for a parent-teacher conference.
"Going to church" implies attending a service for worship etc, wheras "going to the church" implies some other business there, such as visting the priest or delivering something.